But I can see a few potential weaknesses. Slip is the primary one, which will potentially limit its load capacity.
Here's how it works...
http://www.amacoil.com/html/page3a.htm
Basically, it just leans a bearing at an angle, and the pressure angle causes it to track along the length of the linear slide. Positively brilliant. In fact, one of their designs even has an adjustable "thread pitch" that's remotely controllable...can you imagine the possibilities for CNC?
I have some bearings, and some linear slides from an old inkjet printer -- maybe I'll play around with them, a bit, and see if I can get something working!
Anyone else done this, already?
-- Chuck Knigt